U.S. patent application number 11/863553 was filed with the patent office on 2008-07-03 for partitioned chimney cap and fireplace venting system.
This patent application is currently assigned to H. Alfred Eberhardt. Invention is credited to Gary M. Curley, H. Alfred Eberhardt, Bernard T. Wallerich.
Application Number | 20080160894 11/863553 |
Document ID | / |
Family ID | 39584680 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080160894 |
Kind Code |
A1 |
Eberhardt; H. Alfred ; et
al. |
July 3, 2008 |
PARTITIONED CHIMNEY CAP AND FIREPLACE VENTING SYSTEM
Abstract
A fireplace chimney cap includes a body having first and second
apertures in fluid communication defining a first cavity
therebetween. The first cavity is configured and disposed to
receive combustion air through the first aperture, then through the
second aperture for delivery to a fireplace combustion chamber. The
body has third and fourth apertures in fluid communication defining
a second cavity therebetween. The second cavity is configured and
disposed to receive combustion gases from the fireplace combustion
chamber through the third aperture, then through the fourth
aperture for exhausting exterior of the body. The first and second
cavities are fluidly separated from each other. The first and
fourth apertures are configured and disposed to provide a pitot
effect to more readily draw both combustion air into the first
cavity and combustion gases into the second cavity in response to
the first aperture disposed upwind and fourth aperture position
disposed downwind.
Inventors: |
Eberhardt; H. Alfred; (Marco
Island, FL) ; Wallerich; Bernard T.; (Center Valley,
PA) ; Curley; Gary M.; (Lititz, PA) |
Correspondence
Address: |
MCNEES WALLACE & NURICK LLC
100 PINE STREET, P.O. BOX 1166
HARRISBURG
PA
17108-1166
US
|
Assignee: |
Eberhardt; H. Alfred
Marco Island
FL
|
Family ID: |
39584680 |
Appl. No.: |
11/863553 |
Filed: |
September 28, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11618756 |
Dec 30, 2006 |
|
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11863553 |
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Current U.S.
Class: |
454/4 |
Current CPC
Class: |
F23L 17/02 20130101;
F23J 13/00 20130101; F23J 2211/10 20130101; F24B 1/1808
20130101 |
Class at
Publication: |
454/4 |
International
Class: |
F23J 13/08 20060101
F23J013/08 |
Claims
1. A fireplace chimney cap comprising: a body having a first
aperture and a second aperture in fluid communication defining a
first cavity therebetween, the first cavity configured and disposed
to receive combustion air through the first aperture and then
through the second aperture for delivery to a fireplace combustion
chamber; the body further having a third aperture and a fourth
aperture in fluid communication defining a second cavity
therebetween, the second cavity configured and disposed to receive
combustion gases from the fireplace combustion chamber through the
third aperture and then through the fourth aperture for exhausting
exterior of the body, the first and second cavities fluidly
separated from each other; and wherein the opposed first and fourth
apertures are configured and disposed to provide a pivot effect to
more readily draw both combustion air into the first cavity and
combustion gases into the second cavity in response to the first
aperture disposed upwind and fourth aperture disposed downwind.
2. A fireplace chimney cap comprising: a body having a first
aperture and a second aperture in fluid communication defining a
first cavity therebetween, the first cavity configured and disposed
to receive combustion air through the first aperture and then
through the second aperture for delivery to a fireplace combustion
chamber; the body further having a third aperture and a fourth
aperture in fluid communication defining a second cavity
therebetween, the second cavity configured and disposed to receive
combustion gases from the fireplace combustion chamber through the
third aperture and then through the fourth aperture for exhausting
exterior of the body, the first and second cavities fluidly
separated from each other; and first aperture disposed upwind and
fourth aperture position disposed downwind.
3. The cap of claim 2, wherein the first and fourth apertures are
configured to prevent bird entrance.
4. The cap of claim 1, wherein the body includes a partition
disposed between the first and second cavities.
5. The cap of claim 4, further comprising a partial partition
disposed adjacent the first aperture.
6. The cap of claim 1, further comprising a plurality of vanes
associated with at least one of the first and fourth apertures.
7. The cap of claim 6, wherein at least one of the plurality of
vanes is curved.
8. The cap of claim 1, wherein the first and fourth apertures are
oriented at an angle from corresponding upwind and downwind
directions.
9. The cap of claim 8, wherein the angle is about 90 degrees.
10. The cap of claim 8, further comprising a plurality of vanes
associated with at least one of the first and fourth apertures.
11. The cap of claim 8, wherein a portion of at least one vane of
the plurality of vanes associated with the first aperture is
disposed upwind.
12. The cap of claim 8, wherein a portion of at least one vane of
the plurality of vanes associated with the fourth aperture is
disposed downwind.
13. The cap of claim 1, wherein the body is configured to be
securable to differently sized chimney flues.
14. The cap of claim 2, wherein the body is configured to be
securable to differently sized chimney flues.
15. The cap of claim 1, wherein the body is configured to
selectably receive a blower in at least one of the first cavity and
the second cavity.
16. The cap of claim 2, wherein the body is configured to
selectably receive a blower in at least one of the first cavity and
the second cavity.
17. The cap of claim 15, wherein the blower received by the body is
selectable from a plurality of different constructions.
18. A method of installing a fireplace chimney cap to a chimney
flue, the steps comprising: providing a body having a first
aperture and a second aperture in fluid communication defining a
first cavity therebetween, the first cavity configured and disposed
to receive combustion air through the first aperture and then
through the second aperture for delivery to a fireplace combustion
chamber, the body further having a third aperture and a fourth
aperture in fluid communication defining a second cavity
therebetween, the second cavity configured and disposed to receive
combustion gases from the fireplace combustion chamber through the
third aperture and then through the fourth aperture for exhausting
exterior of the body, the first and second cavities fluidly
separated from each other; selectably installing a blower in at
least one of the first and second cavity; securing the body to a
chimney flue with the first aperture disposed upwind, thereby
establishing a pivot effect to more readily draw both combustion
air into the first cavity and combustion gases into the second
cavity.
19. The method of claim 18, wherein the installed blower is
selectable from a plurality of different constructions.
20. The method of claim 18, wherein the step of installing a blower
includes a step of securing a conduit to a blower installed in the
first cavity and to a combustion air supply opening configured for
conveying the combustion air from exterior of the body to the
combustion chamber.
21. The method of claim 18, wherein the step of installing a blower
includes a step of securing a conduit to a blower installed in the
second cavity and to a flue opening configured for conveying the
combustion gases from the combustion chamber to exterior of the
body.
22. A fireplace venting system comprising: a heat exchanger
assembly having a combustion chamber, a chimney flue having an
opening connected to a top portion of the combustion chamber, a
heat source disposed within the combustion chamber for producing
hot gases in response to combustion, a front opening, and a
fireplace screen or the like for closing the front opening to
separate the combustion chamber from an area to be heated, the heat
exchanger assembly comprising: a baffle for sealing the chimney
opening, the baffle having at least one flue opening for exhausting
combustion gases into the chimney flue and at least one combustion
air supply opening for receiving combustion air into the combustion
chamber; at least one elongated heat exchanger core having an outer
hollow member with opposing combustion gas inlet and outlet ends
separated by an outer member length, and an inner hollow member
disposed within and generally coextensive with the outer hollow
member forming an annular passageway therebetween, the inner hollow
member having a medium inlet end and a medium outlet end, and
further defining an interior passageway for a heat transfer medium
flowing generally from the medium inlet end toward the medium
outlet end, at least a portion of combustion gas flow within the
annular passageway being generally in a counter-flow heat exchange
relationship with the medium flow within the inner hollow member,
the annular passageway receiving combustion gases from the
combustion chamber at the gas inlet end and discharging combustion
gases from the gas outlet end; and at least one nozzle disk
configured and disposed in the annular passageway to induce a
swirling flow pattern of the combustion gases about the inner
hollow member generally between the combustion gas inlet and outlet
ends; and a supply conduit in flow communication with the medium
inlet end for directing a flow of the heat transfer medium toward
the medium inlet end of the inner hollow member and a return
conduit in flow communication with the medium outlet end for
receiving the heat transfer medium from the medium outlet end of
the inner hollow member; and a fireplace chimney cap comprising: a
body having a first aperture and a second aperture in fluid
communication defining a first cavity therebetween, the first
cavity configured and disposed to receive combustion air through
the first aperture and then through the second aperture for
delivery to the fireplace combustion chamber; the body further
having a third aperture and a fourth aperture in fluid
communication defining a second cavity therebetween, the second
cavity configured and disposed to receive combustion gases from the
fireplace combustion chamber through the third aperture and then
through the fourth aperture for exhausting exterior of the body,
the first and second cavities fluidly separated from each other;
and wherein the opposed first and fourth apertures are configured
and disposed to provide a pivot effect to more readily draw both
outside air into the first cavity and flue gas into the second
cavity in response to the first aperture disposed upwind and fourth
aperture disposed downwind.
23. The cap of claim 22, wherein the body is configured to
selectably receive a blower in at least one of the first cavity and
the second cavity.
24. The cap of claim 23, wherein the blower received by the body is
selectable from a plurality of different constructions.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a continuation in part of application
Ser. No. 11/618,756, filed Dec. 30, 2006, Attorney Docket No.
2006-030, entitled "FIREPLACE HEAT EXCHANGER" and which is
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to fireplace
accessories and, more particularly, to a fireplace chimney cap
adaptable to a wide array of fireplace sizes and useful for
improving the heating efficiency of a fireplace.
BACKGROUND OF THE INVENTION
[0003] Conventional fireplaces are inefficient sources of heat for
the room in which they are located as the majority of the heat
generated by the combustion process escapes through the chimney.
Fireplace fires also require large volumes of combustion air, which
if drawn from the interior space of the room, result in significant
heat loss from the room as heated room air is also exhausted
through the chimney. Cold air drafts in the interior space also
result since the heat loss through the chimney causes cold air to
be drawn in from the outside through door and window openings.
[0004] In an effort to increase the efficiency of fireplaces,
fireplace inserts have been used. These devices generally comprise
a large metal box situated within the fireplace and extending into
the room in which the fireplace is located. Wood or other fuel is
burned within the large metal box, which has openings for supplying
combustion air and for expelling combustion gases to the chimney.
Room air circulated within the large metal box is heated and
returned to the room without commingling with the combustion air
stream. While such inserts have been designed to retain the visual
appeal and rustic charm of an open flame, their heat transfer
efficiency is limited, allowing substantial amounts of energy to be
exhausted through the chimney to the outside.
[0005] U.S. Pat. No. 4,357,930 and its progeny disclose a fireplace
heating system for heating the room air incorporating a compact
heat exchanger mounted at the top portion of the combustion chamber
of the fireplace and extending across the location where the
chimney flue connects with the top portion of the combustion
chamber. A conventional fireplace door may be used to prevent room
air from being exhausted through the chimney and isolate hotter
portions of the fire from accidental contact by room occupants. A
fan is provided for circulating room air through the heat exchanger
in a manner so that the hot combustion gases heat up the room air
being circulated therethrough without commingling. The design of
the compact heat exchanger directs hot combustion gases through
tortuous pathways to increase heat transfer; the complex design of
the pathways results in increased fabrication costs for the heat
exchanger assembly compared to more conventional heat exchange
methods.
[0006] It would be desirable to provide an improved fireplace
heating and venting system suitable for use in existing or newly
constructed fireplaces that further increases thermal efficiency of
a fireplace, reduces the amount of heat energy exhausted through
the chimney flue, generating reduced levels of noise during
operation and that can be economically fabricated from inexpensive,
yet durable materials.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a fireplace chimney cap
including a body having a first aperture and a second aperture in
fluid communication defining a first cavity therebetween. The first
cavity is configured and disposed to receive combustion air through
the first aperture and then through the second aperture for
delivery to a fireplace combustion chamber. The body further has a
third aperture and a fourth aperture in fluid communication
defining a second cavity therebetween. The second cavity is
configured and disposed to receive combustion gases from the
fireplace combustion chamber through the third aperture and then
through the fourth aperture for exhausting exterior of the body.
The first and second cavities are fluidly separated from each
other. The opposed first and third apertures are configured and
disposed to provide a pivot effect to more readily draw both
combustion air into the first cavity and combustion gases into the
second cavity in response to the first aperture disposed upwind and
fourth aperture disposed downwind.
[0008] The present invention additionally relates to a fireplace
chimney cap including a body having a first aperture and a second
aperture in fluid communication defining a first cavity
therebetween. The first cavity is configured and disposed to
receive combustion air through the first aperture and then through
the second aperture for delivery to a fireplace combustion chamber.
The body further has a third aperture and a fourth aperture in
fluid communication defining a second cavity therebetween. The
second cavity is configured and disposed to receive combustion
gases from the fireplace combustion chamber through the third
aperture and then through the fourth aperture for exhausting
exterior of the body. The first and second cavities are fluidly
separated from each other and first aperture is disposed upwind and
fourth aperture is disposed downwind.
[0009] The present invention further relates to a method of
installing a fireplace chimney cap to a chimney flue. The steps
include providing a body having a first aperture and a second
aperture in fluid communication defining a first cavity
therebetween. The first cavity is configured and disposed to
receive combustion air through the first aperture and then through
the second aperture for delivery to a fireplace combustion chamber.
The body further has a third aperture and a fourth aperture in
fluid communication defining a second cavity therebetween. The
second cavity is configured and disposed to receive combustion
gases from the fireplace combustion chamber through the third
aperture and then through the fourth aperture for exhausting
exterior of the body, the first and second cavities fluidly
separated from each other. The method further includes selectably
installing a blower in at least one of the first and second cavity.
The method further includes securing the body to a chimney flue
with the first aperture facing a predetermined wind direction
thereby establishing a pivot effect to more readily draw both
combustion air into the first cavity and combustion gases into the
second cavity.
[0010] The present invention yet further relates to a fireplace
venting system including a heat exchanger assembly having a
combustion chamber, a chimney flue having an opening connected to a
top portion of the combustion chamber, a heat source disposed
within the combustion chamber for producing hot gases in response
to combustion, a front opening, and a fire screen assembly or the
like for closing the front opening to separate the combustion
chamber from an area to be heated. The heat exchanger assembly
includes a baffle for sealing the chimney opening, the baffle
having at least one flue opening for exhausting combustion gases
into the chimney flue and at least one combustion air supply
opening for receiving combustion air into the combustion chamber.
At least one elongated heat exchanger core has an outer hollow
member with opposing combustion gas inlet and outlet ends separated
by an outer member length, and an inner hollow member disposed
within and generally coextensive with the outer hollow member
forming an annular passageway therebetween. The inner hollow member
has a medium inlet end and a medium outlet end, and further
defining an interior passageway for a heat transfer medium flowing
generally from the medium inlet end toward the medium outlet end.
At least a portion of combustion gas flow within the annular
passageway is generally in a counter-flow heat exchange
relationship with the medium flow within the inner hollow member.
The annular passageway receives combustion gases from the
combustion chamber at the gas inlet end and discharging combustion
gases from the gas outlet end. At least one nozzle disk is
configured and disposed in the annular passageway to induce a
swirling flow pattern of the combustion gases about the inner
hollow member generally between the combustion gas inlet and outlet
ends. A supply conduit is in flow communication with the medium
inlet end for directing a flow of the heat transfer medium toward
the medium inlet end of the inner hollow member. A return conduit
is in flow communication with the medium outlet end for receiving
the heat transfer medium from the medium outlet end of the inner
hollow member. A fireplace chimney cap includes a body having a
first aperture and a second aperture in fluid communication
defining a first cavity therebetween. The first cavity is
configured and disposed to receive combustion air through the first
aperture and then through the second aperture for delivery to the
fireplace combustion chamber. The body further has a third aperture
and a fourth aperture in fluid communication defining a second
cavity therebetween. The second cavity is configured and disposed
to receive combustion gases from the fireplace combustion chamber
through the third aperture and then through the fourth aperture for
exhausting exterior of the body. The first and second cavities are
fluidly separated from each other. The opposed first and third
apertures are configured and disposed to provide a pivot effect to
more readily draw both outside air into the first cavity and flue
gas into the second cavity in response to the first aperture
disposed upwind and fourth aperture disposed downwind.
[0011] An advantage of the present invention is a fan/motor
arrangement for drawing air through the chimney flue to the
combustion chamber of a fireplace system and for drawing combustion
gases from the combustion chamber through the chimney flue, which
arrangement operating at a substantially reduced noise level as
measured adjacent to the combustion chamber.
[0012] A further advantage of the present invention is a fireplace
chimney cap that provides a pivot effect which improves operational
efficiency associated with movement of combustion air and
combustion gases through the fireplace system.
[0013] A still further advantage of the present invention is a
blower fan/motor arrangement for drawing combustion gases from the
combustion chamber through the chimney flue of a fireplace system,
which system will operate at a substantially reduced noise
level.
[0014] A yet further advantage of the present invention is a blower
fan arrangement making possible a chimney of significantly reduced
height. In one embodiment, ranch style residential dwellings may be
constructed without requiring disproportionably high chimneys.
Architects may then incorporate workable masonry fireplaces in
their designs, such as a top floor in a dwelling having vista
living/den rooms or bed room.
[0015] Other features and advantages of the present invention will
be apparent from the following more detailed description of the
preferred embodiment, taken in conjunction with the accompanying
drawings which illustrate, by way of example, the principles of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a fireplace venting system
of the present disclosure.
[0017] FIG. 2 is a perspective view of a fireplace of the present
disclosure.
[0018] FIG. 2A is an exploded view of the fireplace of FIG. 2 of
the present disclosure.
[0019] FIG. 3 is a partial cutaway view taken along line 3-3 of
FIG. 2 of the present disclosure.
[0020] FIG. 4 is a partial cutaway view taken along line 4-4 of
FIG. 2 of the present disclosure.
[0021] FIG. 5 is a partial cutaway view taken along line 5-5 of
FIG. 2 of the present disclosure.
[0022] FIG. 6 is a partial cutaway view taken along line 6-6 of
FIG. 2 of the present disclosure.
[0023] FIG. 6A is a partial cutaway view taken along line 6-6 of
FIG. 2 of the present disclosure.
[0024] FIG. 7 is a partial cutaway view taken along line 7-7 of
FIG. 1 of the present disclosure.
[0025] FIG. 7A is an elevation view of an alternate embodiment of
FIG. 7 of the present disclosure.
[0026] FIG. 8 is a cross-section taken along line 8-8 of FIG. 1 of
the present disclosure.
[0027] FIG. 9 is an embodiment of a nozzle disk of FIG. 2 of the
present disclosure.
[0028] FIG. 10 is a partial cross-section taken along line 10-10 of
FIG. 9 of the present disclosure.
[0029] Other features and advantages of the present invention will
be apparent from the following more detailed description of the
preferred embodiment, taken in conjunction with the accompanying
drawings which illustrate, by way of example, the principles of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] In FIGS. 1, 2 and 2A, there is shown a perspective view (and
an exploded perspective view in FIG. 2A) of a fireplace 5
comprising a combustion chamber 10 having a front opening 12 (FIG.
2), a back wall 14, a pair of side walls 16, a hearth 18, and a
chimney 21 including a chimney flue 20 connected to the top portion
of the combustion chamber 10 by a throat or chimney opening 19.
Combustion gases 37 produced in combustion chamber 10 are
discharged through the chimney flue 20 by way of the throat or
chimney opening 19, and then through a chimney cap 102. In one
embodiment, fireplace venting system 3 conveys relatively cold
outside air or combustion air 35 through chimney cap 102 and then
through chimney flue 20 to combustion chamber 10, as will be
discussed in further detail below.
[0031] FIGS. 1 and 2 further shows a suitable type of gas log
burner 30 for producing heat energy that is supplied with heating
gas from an external source. These gas log burners 30 are well
known in the art and various suitable alternate types may be
employed. Also provided is a conventional fireplace screen 24,
which closes and substantially seals front opening 12, thereby
separating combustion chamber 10 from a room or area to be heated
by fireplace 5. In one embodiment, fireplace screen 24 includes
glass doors or other substantially optically transparent structure
that allow room or area occupants to observe the combustion flames
and that may be opened to access the combustion chamber 10 or for
cleaning the fire screen assembly. However, fireplace screen 24
also includes translucent or opaque constructions in alternate
embodiments.
[0032] In one embodiment, combustion air 35 enters combustion
chamber 10 via a pair of conduits 31 adjacent to and is supplied to
gas log burner 30. Conduits 31 are controllably spaced adjacent to
supply conduit 80 and above hearth 18 by clamps 39 secured in side
walls 16. When the fireplace is not used for extended period of
time, such as during the summer months, clamps 39 are loosened and
the ends of conduits 31 are directed toward hearth 18. When the
ends of conduits 31 are brought into abutment with hearth 18,
access to combustion chamber 10 through conduits 31 is
substantially blocked, preventing insect access into the dwelling
through the chimney. In one embodiment, as shown in FIG. 3, end
portions 41 of conduits 31 are angled toward back wall 14 and
hearth 18 to provide a swirling movement of combustion air 35
within combustion chamber 10. The hot combustion gases 37 produced
by gas log burner 30 will flow upwardly from the location of the
burner combustion immediately above the hearth 18, which upwardly
flowing gases being confined by back and side walls 14, 16 of the
fireplace and fireplace screen 24. Fireplace elements are well
known in the art and are discussed extensively in U.S. Pat. Nos.
4,357,930, 4,471,756, and 6,047,695, all by Eberhardt and which are
incorporated by reference in their entirety herein.
[0033] In accordance with the invention, as shown in FIGS. 2, 2A
and 4, there is provided a heat exchanger assembly 40 comprising
one or more elongated heat exchanger cores 42 and means for
mounting the same within combustion chamber 10, generally adjacent
to back wall 14. In one embodiment, heat exchanger assembly 40 is
substantially vertically oriented. Heat exchanger assembly 40
incorporates a plurality of heat exchanger cores 42 to enable
efficient thermal energy exchange between a heat transfer medium
52, such as room air, and combustion gases 37 by virtue of
non-mixing adjacent flow within the heat exchanger assembly 40. As
shown in FIG. 1, flue baffle 22 is positioned to extend across the
throat or chimney opening 19 in the top portion of the combustion
chamber 10 to seal the connection between combustion chamber 10 and
chimney flue 20. At least one flue opening 28 is provided in baffle
22 to provide combustion gases 37, created when the gas log burner
30 is in operation, a controlled passage from combustion chamber 10
to chimney flue 20. In addition, as further shown in FIG. 1, a pair
of combustion air supply openings 29 formed in baffle 22 provide a
controlled passage of combustion air 35 drawn from exterior of
chimney cap 102 and directed within chimney flue 20 to reach
combustion chamber 10, once the combustion air flows through
respective conduits 31.
[0034] Elements of heat exchanger assembly 40 may be held in
position by anchoring tabs (not shown) secured directly into the
walls 14, 16 of the fireplace which provide connection points for
elements of the heat exchanger assembly. Such anchor tabs are
suitable for use in fireplaces being modified to use the present
invention or fireplaces initially constructed to use the invention.
Alternatively, a free-standing support structure may be provided to
enable the heat exchanger assembly 40 to be self-supporting within
the fireplace, thereby eliminating the need to breach the interior
walls of the fireplace with additional fasteners. The design of a
free-standing support structure is ideally suited for retrofit
applications and is, therefore, adjustable to suit a variety of
fireplace sizes and configurations. Materials selected for support
members, whether a free-standing frame or anchor tabs, are
typically iron or steel and are selected for their durability when
exposed to hot combustion gases in the fireplace and relatively low
cost. However, support members may be composed of other suitable
materials.
[0035] Referring now to FIGS. 2-4, heat exchanger assembly 40
comprises six heat exchanger cores 42 as configured for use in a
typical fireplace. In one embodiment, cores 42 are generally
straight between opposing ends, arranged generally parallel and
generally vertically positioned adjacent the back wall 14 of the
combustion chamber 10. Each heat exchanger core 42 includes an
elongated inner hollow member 44 surrounded by a substantially
coextensive outer hollow member 46 forming an annular passageway 48
therebetween. Both hollow members 44, 46 preferably have generally
circular cross-sections to allow smooth flow of combustion gases 37
and the heat transfer medium 52 (air in the embodiment described
herein), though other shapes or other heat transfer mediums may be
used with reasonable effectiveness. In one embodiment, each core 42
is configured to accept flow of combustion gases 37 and heat
transfer medium 52 in a counter-flow arrangement, that is, the
direction of flow of heat transfer medium 52 in inner hollow member
44 is in a direction generally opposite of the flow of combustion
gases 37 through the outer hollow member 46 for improved heat
exchange performance therebetween.
[0036] As shown in FIGS. 4 and 6, the heat exchanger cores 42 are
configured and disposed so that adjacent outer hollow members 46
abut each other along the longitudinal direction, or direction of
elongated length. There are three pairs of cores 42 in which
combustion gases 37 flow in a downward helical direction through
annular passageway 48 of one core 42. Upon reaching transition
region 61, the direction of flow of combustion gases 37 is reversed
so that the combustion gases 37 flow in an upward helical direction
through annular passageway 48 of the adjacent core 42 of the pair
of cores 42. The change in direction of combustion gases is shown
in FIGS. 4, 5 and 6A.
[0037] As previously discussed, hot combustion gases 37 traveling
within passageways 48 (FIGS. 4 and 6) of heat exchanger cores 42
toward the bottom of combustion chamber 10 are redirected to flow
within passageways 48 of adjacent heat exchanger cores 42 toward
the top of combustion chamber 10. As further shown in FIGS. 1, 2, 4
and 6A, once the combustion gases 37 approach the top of heat
exchanger assembly 40, combustion gases 37 passing through
combustion gas outlet opening 96 are directed inside a plenum 54
having a vane 67. Vane 67 divides plenum 54 into passageways 56 and
57. Passageway 56 receives combustion gases 37 from annular
passageway 48 and passageway receives heated heat transfer medium
53 from inner hollow member 44. As shown in FIG. 2A, plenum 54
includes a pair of slots 55 (one slot shown in FIG. 2A), each slot
receiving a corresponding pin 59 of a pair of pins 59 (one pin
shown in FIG. 2A) formed in an insert 60. The resulting pivoting
connections formed between plenum 54 and insert 60 accommodate the
range of angles between back wall 14 and flue baffle 22. Insert 60
includes a tube having a vane 62 terminating at an end cap 77 which
forms a chamber 63 that is in fluid communication with fitting 71
secured to the exterior of insert 60. A conduit portion 68 is
configured to receive conduit portion 66. Collectively, as shown in
FIG. 2A, insert 60, and conduit portions 66, 68 define return
conduit 90.
[0038] In operation, as shown in FIGS. 1, 2A and 6A, plenum 54 is
disposed between heat exchanger core 42 and insert 60 such that
combustion gases 37 passing through combustion gas outlet opening
96 are directed through passageway 56 and then into chamber 63 of
insert 60. Plenum 54 and insert 60 form an overlap 78 in which vane
67 of plenum 54 and vane 62 of insert 60 form a substantially fluid
tight seal to substantially prevent combustion gases 37 from mixing
with heated heat transfer medium 53. In one embodiment, the curves
defining passageway 56 act to preserve a portion of the momentum of
the flow of combustion gases 37. Combustion gases 37 entering
chamber 63 then flow through opening 64 of insert 60, then through
fitting 71 of insert 64, which extends through flue opening 28
formed in flue baffle 22.
[0039] The conventional throat or chimney opening 19 is sealed in
the present disclosure by the presence of flue baffle 22. As a
result, all hot combustion gases 37 are directed through the heat
exchanger assembly 40 prior to being discharged into chimney flue
20. In one embodiment, one end of conduit 33, such as flexible
aluminum tubing, is secured over fitting 71 that extends through
flue opening 28, with the other end secured to an inlet aperture
112 of chimney cap 102 that is in fluid communication with an
outlet aperture 114 for discharging combustion gases 37 exterior of
fireplace venting system 3. In other words, combustion gases 37 are
confined to flow inside conduit 33 and do not mix with combustion
air 35 passing through chimney cap 102 and into chimney flue 20,
which combustion air 35 being conveyed to combustion chamber
10.
[0040] As shown in FIGS. 1, 7 and 8, chimney cap 102 includes a
body 104 defining a substantially trapezoidal profile extending in
a longitudinal direction, i.e., the direction of primary length.
Body 104 contains partitioned cavities 110, 116 disposed therein
for separately receiving combustion air 35 and discharging
combustion gases 37 therethrough. A louvered inlet aperture 106
including vanes 120 disposed therealong is formed in body 104 for
receiving combustion air 35 into cavity 110 from exterior of body
104. Adjacent to inlet aperture 106 is a partial partition 122 that
is proximate to a full partition 118. In one embodiment, the
louvers of inlet aperture 106 are spaced to prevent access, such as
by birds.
[0041] Partial partition 122, which may span body 104 in the
transverse direction in one embodiment, prevents rain or other form
of moisture from entering cavity 110 and provides additional
structural stiffness to body 104. Full partition 118, shown as
including three panel segments joined along their edges and
disposed at angles from each other, forms a contiguous wall in body
104 to separate cavity 110 from another cavity 116. An outlet
aperture 108 (FIG. 8) is disposed between full partition 118 and
partial partition 122 for discharging combustion air 35 received
into cavity 110 through inlet aperture 106. Combustion air 35
discharged from outlet aperture 108 flows within chimney flue 20
toward combustion chamber 10.
[0042] Body 104 also includes cavity 116 having an inlet aperture
112 (FIG. 8) for receiving combustion gases 37 from combustion
chamber 10 via conduit 33. In one embodiment, a transition fitting
or adapter 126 (FIG. 7) permits connection of conduit 33 and a
blower 128 secured inside cavity 116. Blower 128 draws combustion
gases 37 through conduit 33 and then inside cavity 116 through
inlet aperture 112, finally discharging the combustion gases
exterior of body 104 through louvered outlet aperture 114 having
vanes 120. In one embodiment, the louvers of outlet aperture 114
are spaced to prevent access, such as by birds.
[0043] As shown, inlet aperture 106 and outlet aperture 114 are
opposed from each other, separated from each other by a flue liner
124 (FIG. 7) when chimney cap 102 is installed. Due to the opposed
construction, in response to orienting inlet aperture 106 so that
inlet aperture 106 is disposed upwind or faces the general
direction of the wind, i.e., the northwest in many portions of
North America, body 104 experiences a pivot effect with respect to
each of inlet aperture 106 and outlet aperture 114. That is, when
inlet aperture 106 is oriented to face the wind, the relative
atmospheric pressure developed outside of but in close proximity
with cavity 110 is increased with respect to the relative
atmospheric pressure developed inside cavity 110, due to the
combustion air 35 colliding with flue liner 124, thereby drawing
combustion air 35 through inlet aperture 106 and into cavity 110.
Conversely, when outlet aperture 114 is disposed downwind or
oriented to face opposite the wind, the relative atmospheric
pressure developed outside of but in close proximity with cavity
116 is reduced with respect to the relative atmospheric pressure
developed inside cavity 116, due to the wind flowing around flue
liner 124, thereby drawing combustion gases 37 from cavity 116
through outlet aperture 114.
[0044] It is to be understood that the term "facing the wind" or
"facing upwind" in reference to apertures 106 and 114 is intended
to include circumstances in which a plane (not shown) defining
apertures 106 and 114 are disposed at an angle to the direction of
travel of the wind, including parallel to the wind, and also
includes circumstances in which apertures 106 and 114 are disposed
to the wind at angles different from parallel. With assistance of a
sustained pivot effect, the load required by blower 128 to
discharge combustion gases 37 from conduit 33 through and then
exterior of chimney cap 102 is reduced.
[0045] The pivot effect may be enhanced through the use of vanes
120 staggered to be disposed upwind or directly face the wind. That
is, as shown in FIG. 7, a plane 130 of inlet aperture 106 is
disposed at an angle .theta. to the horizontal. Thus, wind that is
horizontally disposed combustion air 35 strikes each of vanes 120
distributed over inlet aperture 106, thereby enhancing the pivot
effect described above. It is to be understood that vanes 120 may
be of similar or of different sizes, so that a portion of each vane
is directly exposed to wind emanating from a predominant direction
and orientation, such as horizontally oriented wind from the
northwest. For example, as shown in FIG. 7A, vanes 120 are
substantially planar, versus being curved in FIG. 7. In addition,
vanes 120 in FIG. 7A are entirely contained within respective
cavities 110, 116.
[0046] As shown in FIGS. 7 and 8, chimney cap 102 includes features
permitting use with differently configured blowers 128. That is,
chimney cap 102 can accommodate different blower sizes and shapes.
Adjustable fastening members 134, such as threaded rod, and
associated mating fastener members 136, such as jam nuts, may be
used to secure blower 128 via a blower flange 138 and openings 132
formed in body 104. In one embodiment, the pattern of openings in
blower flange 138, openings 132 and openings 148 of chimney cap 102
are substantially identical, and plate 152 is separable from body
104.
[0047] In one embodiment, adjustable brackets 142 support chimney
cap 102 and include opposed pairs of brackets 142 that are disposed
on opposite ends of flue liner 124. The opposed pairs of brackets
142 include slots 144 for use with mating fasteners 150 to
accommodate differently sized flue liners 124. Additionally,
brackets 142 include fasteners 146, such as set screws, for
securing brackets 142 and chimney cap 102 in position to flue liner
124. Moreover, brackets 142 secure a transition fitting or adapter
126 between blower 128 and conduit 33, such as a reducer, which
transition fitting or adapter 126 structurally supports the weight
of conduit 33.
[0048] In one non-limiting method of assembly of chimney cap 102 to
flue liner 124, transition fitting or adapter 126 is secured to
each opposed pair of brackets 142, then conduit 33 is secured to
transition fitting or adapter 126 prior to lowering conduit 33
inside of flue liner 124. Once conduit 33 has been lowered, the
opposed pairs of brackets can then be secured to flue liner 124
with fasteners 146, such as set screws. In one embodiment, plate
152 is separable from body 104. Plate 152 is secured via openings
132 to such as respective openings (not shown) formed in brackets
142 using fastening members 134 and 136, such as respective
threaded rod and jam nuts, as shown, which fastening members are
further utilized to secure flanges 138 to blower 128. At this
point, in one embodiment, four ends of fastening members 134 extend
upwardly. Body 104 is then lowered over fastening members 134,
aided by guides 140 so that ends of fastening members 134 extend
through corresponding openings 148 aligned with the guides.
Assembly is then completed by securing fasteners 154, such as cap
screws, over each fastening member 134.
[0049] Referring back to FIGS. 2, 2A and 3-6, each heat exchanger
core 42 is made of a material to provide a highly heat conductive
arrangement. To that end, inner hollow member 44 is constructed of
a heat conductive material, such as aluminum, to effectively
conduct heat from the hot combustion gases 37 flowing through the
annular passageway 48 to the heat transfer medium 52 flowing
through the inner hollow member 44. Outer hollow member 46, which
is directly exposed to the combustion occurring at burner 30, is
likewise constructed of a highly heat conductive material, but one
that is also more suitable for the combustion chamber environment,
such as steel and, more specifically, stainless steel.
[0050] In one embodiment, the heat exchanger assembly 40 is
configured such that inlet and outlet openings 86, 96 for the inner
hollow members 44 and the annular passageways 48 are generally
adjacent and proximate to a common end of the assembly 40.
[0051] In one embodiment, the aluminum inner hollow members 44 and
other aluminum parts of the heat exchanger cores 42 are anodized
flat black. This improves the heat transfer properties of these
parts by improving the heat transfer coefficient thereof. The
overall heat transfer effectiveness of the heat exchanger assembly
40 is improved by the addition of a radiant energy reflector 65 to
at least a portion of the heat exchanger assembly 40. In one
embodiment, radiant energy reflector 65 is a contiguous component
as shown in FIG. 2A, simultaneously serving as an access cover for
blower or fan/motor assembly 100, although multiple reflectors may
be used. The radiant energy reflector 65 may be in the form of a
reflective covering, such as polished stainless steel or the like,
on at least a portion of the outer hollow members 46. By
positioning radiant energy reflector 65 on or along a portion of
the heat exchanger core 42 adjacent to the burner 30, radiant heat
energy from the combustion flames of the burner is thereby directed
toward the room or space to be heated. Radiant energy reflector 65
may also be in the form of a material selection and/or exterior
surface treatment of the outer hollow members 46 to provide the
desired surface reflective characteristics.
[0052] Each heat exchanger core 42 is constructed and arranged to
increase the dwell time of hot combustion gases 37 in the annular
passageway 48 thereby increasing the heat transfer between the
relatively hotter combustion gases and the relatively cooler heat
transfer medium 52. An object is to extract as much thermal energy
as possible in a relatively compact space. By doing so, materials
of construction for the chimney flue can be selected having to
withstand much lower temperatures, as low as about 150.degree. F.
in at least one embodiment, thereby allowing less expensive
materials to be used for the chimney flue, such as PVC. To this
end, the heat exchanger cores 42 are configured to cause a vortex
flow of the combustion gases 37 as they flow through the annular
passageway 48. The vortex flow is caused by at least one nozzle
disk 70 (FIGS. 2A, 6 and 9-10), which is connected to at least one
of the inner and outer hollow members 44, 46 and positioned
proximate to the inlet end 86 (FIG. 6) of the annular passageway
48. As hot combustion gases pass through nozzle disk 70, the gases
are forced to swirl about the annular passageway 48 (e.g., FIG. 6),
generally circulating around the inner hollow member 44 as the
gases proceed along the length of the heat exchanger core 42.
Referring to FIG. 4, combustion gases 37 flowing downwardly through
heat exchanger core 42 rotate generally counterclockwise, when
viewed from above, about the inner hollow member 44 as the gases
downwardly traverse the annular passageway 48. While the rotation
for the upwardly directed combustion gases is opposite that of the
downwardly directed combustion gases 37, as shown in FIGS. 4 and 5,
in another embodiment (not shown), the rotational directions of
combustion gases 37 are the same in both directions. The direction
of spin for at least the downwardly directed combustion gases 37 in
the annular passageways 48 is selected to be aided by the Coriolis
effect of the earth's rotation, further enhancing the spinning
motion of the combustion gases traversing through the annular
passageways. Those skilled in the art will appreciate the direction
of spin shown corresponds to the Coriolis effect in the northern
hemisphere, so that an installation for use in the southern
hemisphere should be configured to cause a spin in a reverse
direction.
[0053] FIGS. 9 and 10 show details of the nozzle disk 70, which
disk positioned proximate to the inlet end 86 of each annular
passageway 48. In one embodiment, nozzle disks 70 may be
interconnected to each other. In one embodiment, nozzle disk 70 is
of generally planar circular construction, having an outer
perimeter 72 generally matching the inner perimeter of outer hollow
member 46 (FIG. 4), and an inner opening structure 74 through which
the inner hollow member 44 (FIG. 4) passes. In one embodiment,
inner and outer hollow members 44, 46 and nozzle disk 70 are
arranged along a common centerline corresponding to the
longitudinal axis of the hollow members 44, 46. A plurality of vane
structures 76 is arranged generally radially about the centerline.
The vane structures include a penetration 73 through the nozzle
disk structure and a flow directing vane 75 positioned such that
hot combustion gases passing through the penetrations 73 impinge on
the flow directing vane and are deflected. Each flow directing vane
75 defines an inclination angle .PHI. with respect to the plane of
the nozzle disk, approximately 30 degrees in one embodiment, but
those skilled in the art will recognize that a wide variation in
the angle of inclination can be used without deviating from the
functional objective of the nozzle disk 70. Gaps between the inner
and outer hollow member 44, 46 walls and the nozzle disk 70 are
minimized by a tight-fitting interface so that combustion gases
bypassing the nozzle disk will be minimized.
[0054] Referring now to FIGS. 2, 2A, 3-6 and 6A, there is shown one
embodiment for circulating heat transfer medium 52, room air in one
embodiment, through the heat exchanger assembly 40 to heat the
adjacent space. Once heat transfer medium 52 is heated after
passing through heat exchanger assembly 40, it is designated as
heated heat transfer medium 53. As shown, a supply conduit 80 is
employed to convey heat transfer medium 52, and a return conduit 90
is employed to convey heat transfer medium 53.
[0055] In operation, a fan/motor assembly 100 draws relatively cool
heat transfer medium 52 from the space or room and directs it
through supply conduit 80 toward the heating medium inlet opening
84 of the heat exchanger core 42. To simplify installation and
accommodate fireplaces of different size, supply conduit 80
includes several portions that slidingly overlap each other.
[0056] In one embodiment, after being directed through fan/motor
assembly 100, heat transfer medium 52 enters plenum 58 which
defines a region of increasing cross-sectional area between the
lower and upper end of plenum 58, as measured by horizontal planes
(not shown). In other words, plenum 58 increases in arial
transverse directions between the lower and upper end of plenum 58,
as shown orthogonally in FIGS. 3 and 4. This increase in
cross-sectional area significantly reduces the velocity of entering
heat transfer medium 52 without decreasing the energy associated
with the fluid flow from fan/motor assembly 100. In addition, as
shown in FIG. 4, one or more vanes 83 are disposed within plenum 58
to selectably redirect a portion of the flow of heat transfer
medium 52 to at least the outermost positioned heat exchanger cores
42. Vanes 83 are configured to redirect flow of heat transfer
medium 52 to more evenly distribute the amount of the medium
flowing through each heat exchanger core 42 while minimizing a
reduction of energy associated with the fluid flow from fan/motor
assembly 100.
[0057] After exiting plenum 58, heat transfer medium 52 enters the
interior of inner hollow member 44 through the heating medium inlet
opening 84 and moves through the heat exchanger cores 42 while
absorbing thermal energy from the hot combustion gases 37 that are
spinning around the outer surface of the inner hollow member 44.
After passing through the heat exchanger cores 42, the heated heat
transfer medium 53 (FIG. 6) then exits the heat exchanger assembly
40 through a heating medium outlet opening 94 and is delivered back
to the area or room to be heated by the return conduit 90.
[0058] It is appreciated that as shown in FIG. 2A, heat exchanger
assembly 40 is similarly able to accommodate fireplaces of
different height due to the overlapping sliding rectangular
portions 79, 81 surrounding heat exchanger cores 42.
[0059] Conduit design may include adjustable and/or flexible supply
and return conduit 80, 90 to enable plenums to be installed in a
variety of fireplace sizes and configurations. While imperative for
retrofit installations where the exact fireplace dimensions are
unknown when the conduits are fabricated, such flexibility may also
benefit purpose-built fireplace installations by enabling a single
conduit design to be used on a range of fireplace sizes. Such
flexible design streamlines production and inventory requirements,
thereby reducing overall cost of production of the invention.
[0060] While the embodiment shown in FIG. 2 describes use of one
embodiment of the disclosure invention for heating a room adjacent
to the fireplace, other alternatives are possible by directing the
air supply and return conduits to other rooms. Those skilled in the
art will recognize that numerous options for directing a heat
transfer medium to and through the heat exchanger assembly are
permissible within the scope of the present invention. While six
generally parallel flow paths are shown in FIG. 4, it is possible
to direct the heat transfer medium in a serial flow through the
entire heat exchanger assembly wherein a single heating medium
inlet opening 84 and a single heating medium outlet opening 94 is
used. Conversely, more or less than six generally parallel flow
paths may also be used since the heat exchanger cores 42 of the
present invention are modular in nature. Adjusting the heating
medium flow rates and the flow configuration through the heat
exchanger cores allows a desired heating medium return temperature
to be selected based on the heat input of the burner assembly.
[0061] In an alternate embodiment, a liquid heat transfer medium
may be circulated through the inner hollow members whereupon the
liquid heat transfer medium absorbs heat energy from the hot
combustion gases. The heated liquid may then be easily conveyed to
other locations where the heat energy may be extracted to provide
heat to a room or another area. An example remote location would be
a heat exchanger positioned in the existing heating system for a
house whereby the heat energy from the fireplace is efficiently
distributed to the entire heated portion of a house or building
structure. Such an application provides further benefit to heat
pump systems, which require a supplemental heat source when outside
air temperatures fall below certain levels. Heat energy from the
fireplace can replace expensive electric resistance heating
elements often used as supplemental heat sources for heat pumps,
potentially lowering energy costs. Due to the modular arrangement
of the heat exchanger assembly, a combination of room air from a
room adjacent the fireplace and a heat transfer liquid directed to
a heat exchanger in a different location may be accommodated,
enabling a single fireplace to effectively heat greater portions of
a house, thereby further increasing the effectiveness of the
fireplace as a supplemental heating source.
[0062] While the invention has been described with reference to a
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended
claims.
* * * * *